[Confiks]

Yet this is exactly what babel-runtime will do for you: include all the polyfills. If you're not targetting IE8 and you don't care about Intl won't actually be that much code.

If you're using webpack you can use the code splitting feature to make sure the browser doesn't download that extra few KBs (which is presumable a trade-off between (an) extra roundtrip(s), so maybe you should just swallow those KBs).